Method for determining suitable development area of large-scale drip irrigation farmland in shallow groundwater area

Abstract

The application discloses a method for determining suitable development area of large-scale drip irrigation farmland in a shallow groundwater area, which comprises the following steps: coupling a MODFLOW model and a SWNCM-2D model based on programming software to develop a coupling model suitable for simulating water and salt migration in saturated and unsaturated zones and crop growth of large-scale drip irrigation farmland in a shallow groundwater area; according to underground water depth control test data of a lysimeter, key parameters of the coupling model are calibrated and verified, multi-scenario simulation under different underground water depths is carried out, and suitable underground water depth under drip irrigation is determined; scenes with different proportions of drip irrigation farmland area are set, the coupling model is used for simulation, suitable underground water depth is taken as a control standard, and suitable development area of large-scale drip irrigation farmland in a shallow groundwater area is determined; and the method provides technical support and quantitative basis for development and field management of large-scale drip irrigation farmland through multi-model coupling, multi-process simulation and multi-scenario analysis.

Description

Technical Field

[0001] This invention relates to the fields of efficient water management in agricultural irrigation areas and groundwater safety technology, specifically to a method for determining the suitable development area of ​​large-scale drip irrigation farmland in shallow groundwater areas. Background Technology

[0002] The Hetao Irrigation District has long suffered from shallow groundwater levels, leading to severe salinization. In recent years, the volume of irrigation water diverted from the Yellow River has decreased annually, exacerbating water shortages, making traditional irrigation methods unsustainable, weakening salt removal efficiency, and increasing the risk of salinization. As a relatively mature water-saving irrigation technology, drip irrigation reduces deep seepage of irrigation water into farmland, resulting in significant water conservation and yield increases. Its strong environmental adaptability has led to its large-scale application in the Hetao Irrigation District. However, deep seepage of irrigation water is also a significant source of groundwater imbalance in the irrigation district. Long-term, large-scale drip irrigation may increase the depth of groundwater in farmland and reduce capillary upwelling, thereby altering the material exchange relationship between groundwater and soil water, making soil water and salt movement more complex. Simultaneously, research shows a strong coupling relationship between crop growth and the dynamic processes of soil water-groundwater material migration and transformation. Therefore, accurately characterizing soil water and salt transport, groundwater dynamics, and crop growth processes under large-scale drip irrigation conditions has become crucial for the large-scale development of drip irrigation in the irrigation district.

[0003] In recent years, mathematical models, due to their lack of spatial and temporal limitations, have become indispensable tools for characterizing water and salt movement under water-saving conditions in irrigation areas. Simulations of water and salt transport in the unsaturated zone, groundwater dynamics in the saturated zone, and crop growth processes have developed rapidly and are widely used in farmland water, fertilizer, and salt management. However, existing unsaturated zone simulations mostly employ vertical one-dimensional soil water and salt models or water balance models, which struggle to accurately characterize the impact of large-scale drip irrigation on soil water and salt transport processes in irrigated farmland. Furthermore, the intercropping of crops in large-scale farmland can alter water and salt transport characteristics, making the application of two-dimensional soil water and salt models highly significant. On the other hand, existing models have made valuable explorations in quantitatively describing the migration, transformation, and absorption of two-dimensional soil moisture, salt, and nitrogen under drip irrigation conditions and the processes affecting crop growth. However, in areas with shallow groundwater depths, the quantitative characterization of the effects of drip irrigation soil water-fertilizer-salt interactions on crop growth still requires systematic and in-depth research.

[0004] In summary, this invention, based on the two-dimensional soil water and nitrogen coupled model (SWNCM-2D) and crop growth coupled model (MODFLOW), realizes the simulation of water and salt transport in saturated and unsaturated zones of drip-irrigated farmland, quantifies water and salt transport and multiple processes of crop growth in large-scale drip-irrigated farmland, determines the suitable development area for large-scale drip irrigation, and provides technical support for the large-scale development of drip irrigation water-saving irrigation area in shallow groundwater areas. Summary of the Invention

[0005] To address the aforementioned shortcomings of existing technologies, this invention provides a method for determining the suitable development area of ​​large-scale drip-irrigated farmland in shallow groundwater areas. This method solves the technical problems mentioned in the background section. It quantifies the soil water and salt transport patterns, groundwater dynamics, and surface vegetation response processes under large-scale drip irrigation conditions based on a groundwater model coupled with a two-dimensional soil water and nitrogen coupled with crop growth model, and uses this method to determine the suitable development area of ​​large-scale drip-irrigated farmland in shallow groundwater areas.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] A method for determining the suitable development area of ​​large-scale drip-irrigated farmland in shallow groundwater areas is provided, comprising the following steps: S1, developing a coupled model suitable for simulating water and salt transport and crop growth in saturated and unsaturated zones of large-scale drip-irrigated farmland in shallow groundwater areas by coupling the MODFLOW model and the SWNCM-2D model using programming software; S2, calibrating and verifying the key parameters of the coupled model based on groundwater depth control test data from lyoinfiltration meters, and conducting multi-scenario simulations at different groundwater depths to determine the suitable groundwater depth under drip irrigation conditions; S3, setting scenarios with different proportions of drip-irrigated farmland area and simulating them using the coupled model, using the suitable groundwater depth as the control standard to determine the suitable development area of ​​large-scale drip-irrigated farmland in shallow groundwater areas.

[0008] Furthermore, the SWNCM-2D model in step S1 is a coupled model of the two-dimensional soil water and salt transport mechanism model and the EPIC crop model. The two-dimensional soil water and salt transport mechanism model is solved by the finite element method to obtain the soil moisture content and soil salinity of each finite element node in the simulation area as a function of simulation time. The water balance and node flux are used to quantify the changes in node water and salt content. At the same time, the soil water and salt data drive the EPIC crop model to simulate crop growth dynamics.

[0009] Furthermore, the MODFLOW model in step S1 is a three-dimensional groundwater transport model, which is solved using the finite difference method to obtain the groundwater level of each cell in the simulation area as a function of simulation time.

[0010] Furthermore, step S1 specifically includes model coupling during the preset simulation time progression, through the mutual transmission of the lower boundary flux of the SWNCM-2D model and the groundwater level simulated by the MODFLOW model. The specific process of model coupling includes:

[0011] S11: When the simulation time is in the initial state, the MODFLOW model and the SWNCM-2D model read the initial information one after another, and then the initial groundwater level of the MODFLOW model is passed to the SWNCM-2D model as its lower boundary condition.

[0012] S12: When the simulation time moves from the initial state to the first groundwater flow accumulation time step, the SWNCM-2D model iteratively solves the unsaturated zone soil water and salt content at a preset time step until the first groundwater flow accumulation time step is reached. Then, it outputs the accumulated lower boundary flux and passes it to the MODFLOW model, which iteratively solves the groundwater level.

[0013] S13: When the simulation time changes from the first groundwater flow cumulative time step to the second groundwater flow cumulative time step, the MODFLOW model transfers the groundwater level calculated in the previous groundwater flow time step to the SWNCM-2D model as the new lower boundary condition, and recalculates and transfers the cumulative lower boundary flux within the groundwater flow time step.

[0014] S14: Repeat steps S12-S13 of the simulation process until the preset simulation time is reached.

[0015] Furthermore, the MODFLOW model transfers the groundwater level to the SWNCM-2D model as a lower boundary condition, expressed as follows:

[0016]

[0017] in, GWL For the lower boundary condition, n The number of cells simulated for the MODFLOW model. H i This represents the groundwater level corresponding to the cell. Z 1 represents the bottom coordinates of the simulation area of ​​the SWNCM-2D model.

[0018] Furthermore, the experimental data in step S2 includes soil moisture content, soil salinity, irrigation amount, rainfall, crop leaf area, crop height, crop yield, groundwater level, and the amount of groundwater directly pumped out or added during the maintenance of the lyostat groundwater level, all measured periodically during the crop growth period.

[0019] Furthermore, the key parameters of the coupled model include soil moisture model parameters, groundwater model parameters, and crop model parameters. Soil moisture model parameters include residual moisture content, saturated moisture content, saturated hydraulic conductivity, and soil moisture characteristic curve shape parameters. Groundwater model parameters include permeability coefficient, water storage rate, and water yield in the direction of water flow. Crop model parameters include maximum temperature for crop growth, minimum temperature for crop growth, maximum leaf area index, and maximum heat unit value required for crop maturity.

[0020] Further, step S2 includes: inputting the key parameters of the coupled model as initial information into the coupled model, outputting simulated values ​​of soil moisture content, soil salinity, crop leaf area, crop plant height, crop yield, and groundwater level from the coupled model, comparing the simulated values ​​with the measured data of the experimental data for error, and adjusting the corresponding key parameters of the coupled model until the error reaches the preset range, thus completing the calibration of the key parameters; resimulating using the calibrated key parameters, checking the error between the simulated values ​​and the experimental data, and verifying the key parameters when the error meets the requirements.

[0021] Furthermore, step S2 also includes: setting different groundwater burial depth scenarios, simulating different groundwater burial depths using a coupled model after calibration and verification of key parameters, comparing soil salinity and crop yield results under different groundwater burial depth scenarios, and determining the burial depth corresponding to the minimum soil salinity and maximum crop yield as the appropriate groundwater burial depth.

[0022] Further, step S3 specifically includes: setting different scenarios of drip irrigation farmland and furrow irrigation farmland area ratios, substituting them into the coupling model for simulation, obtaining the corresponding groundwater level simulation values, comparing the groundwater level simulation values ​​with the suitable groundwater depth, and taking the drip irrigation farmland area in the scenario that is closest to the suitable groundwater depth as the suitable development area for large-scale drip irrigation farmland in the shallow groundwater area.

[0023] The beneficial effects of this invention are as follows:

[0024] 1. This scheme achieves integrated simulation of water and salt transport in the saturated-unsaturated zone and crop growth by coupling the MODFLOW model and the SWNCM-2D model, breaking through the limitations of traditional one-dimensional models in simulating water and salt transport in drip-irrigated farmland; the model coupling is implemented using Fortran programming, which has high computational efficiency and adaptability, and is suitable for large-scale farmland simulation; and through the time-step coupling mechanism of dynamic interaction between groundwater level and lower boundary flux, bidirectional feedback between the unsaturated zone and the saturated zone is realized, making the simulation results closer to reality.

[0025] 2. This scheme uses a lysimeter to control the test calibration and verification of model parameters, ensuring the accuracy of the model under localized conditions. Through multi-scenario simulations with different groundwater depths and different drip irrigation area ratios, the appropriate groundwater depth and suitable drip irrigation development area can be scientifically determined, providing technical support and quantitative basis for the development of large-scale drip irrigation farmland and field management. It can effectively solve the practical problems of drip irrigation water-saving irrigation technology in shallow underground areas.

[0026] 3. This solution can be applied to drip irrigation in shallow groundwater areas such as the Hetao Irrigation District, which can save water and increase production, while also preventing soil salinization and achieving a win-win situation for both economic benefits and ecological security. Attached Figure Description

[0027] Figure 1 A flowchart illustrating the method for determining the suitable development area of ​​large-scale drip irrigation farmland in areas with shallow groundwater.

[0028] Figure 2 A flowchart for a coupled simulation model of water and salt transport and crop growth in saturated and unsaturated zones of drip-irrigated farmland in shallow groundwater areas.

[0029] Figure 3 A structural diagram showing the suitable area for drip irrigation promotion in farmland for this plan. Detailed Implementation

[0030] The specific embodiments of the present invention are described below to enable those skilled in the art to understand the present invention. However, it should be understood that the present invention is not limited to the scope of the specific embodiments. For those skilled in the art, various changes are obvious as long as they are within the spirit and scope of the present invention as defined and determined by the appended claims. All inventions utilizing the concept of the present invention are protected.

[0031] To address the difficulty of existing models in quantitatively characterizing soil water and salt transport in large-scale drip-irrigated farmland in shallow groundwater areas and its impact on crop growth, this invention provides a method for quantifying soil water and salt transport patterns, groundwater dynamics, and surface vegetation response processes under large-scale drip irrigation conditions by coupling the MODFLOW model (saturated zone) and the SWNCM-2D model (unsaturated zone and crop growth), and thereby determining the suitable development area for large-scale drip-irrigated farmland in shallow groundwater areas.

[0032] like Figure 1 As shown, the method for determining the suitable development area of ​​large-scale drip irrigation farmland in shallow groundwater areas in this scheme includes the following steps:

[0033] S1. Based on programming software, a coupled model was developed to simulate water and salt transport in saturated and unsaturated zones and crop growth in large-scale drip-irrigated farmland in shallow groundwater areas, using the MODFLOW model and SWNCM-2D model.

[0034] In specific implementation, the SWNCM-2D model is a coupled model of a two-dimensional soil water and salt transport mechanism model and an EPIC crop model. The finite element method is used to solve the two-dimensional soil water and salt transport mechanism model, obtaining the soil moisture content and soil salinity of each finite element node within the simulation area as a function of simulation time. Water balance, node flux, and boundary flux are used to quantify the changes in node water and salt content. Simultaneously, soil water and salt data drive the EPIC crop model to simulate crop growth dynamics. The MODFLOW model is a three-dimensional groundwater transport model, solved using the finite difference method, obtaining the groundwater level of each cell within the simulation area as a function of simulation time. Both models are based on simulation programs built using the Fortran programming language, and model coupling is achieved by modifying the model's source code. Given initial information, boundary conditions, and empirical model parameters, both models can simulate changes in soil moisture content, soil salinity, boundary flux, groundwater level, plant height, leaf area, and yield within a set time. The unsaturated zone and saturated zone are connected vertically, such as... Figure 2 As shown, the flux at the lower boundary of the unsaturated zone and the water level in the saturated zone influence each other.

[0035] like Figure 3 As shown, in step S1, during the preset simulation time progression, model coupling is achieved through the mutual transmission of the lower boundary flux of the SWNCM-2D model and the groundwater level simulated by the MODFLOW model. The specific process of model coupling includes:

[0036] S11: When the simulation time is in the initial state, the MODFLOW model and the SWNCM-2D model successively read the initial information, and then the initial groundwater level of the MODFLOW model is transferred to the SWNCM-2D model as its lower boundary condition; considering that a single unsaturated zone of simulated farmland corresponds to multiple horizontal grids divided by MODFLOW, such as Figure 2 The subroutine corresponds to multiple cells in cell A1, while a profile only requires one lower boundary condition. Therefore, the main purpose of this subroutine is to average the groundwater level and convert the groundwater level value to the lower boundary condition. The expression by which the MODFLOW model passes the groundwater level to the SWNCM-2D model as the lower boundary condition is:

[0037]

[0038] in, GWL For the lower boundary condition, n The number of cells simulated for the MODFLOW model. H i This represents the groundwater level corresponding to the cell. Z 1 represents the bottom coordinates of the simulation area in the SWNCM-2D model;

[0039] S12: When the simulation time progresses from the initial state to the first groundwater flow accumulation time step, the SWNCM-2D model iteratively solves for the unsaturated zone soil water and salt content at a preset time step until the first groundwater flow accumulation time step is reached. Then, it outputs the accumulated lower boundary flux and passes it to the MODFLOW model, which iteratively solves for the groundwater level. Due to the conversion of simulation dimensions and units, and the multiple unsaturated zone profiles that will appear during application, a subroutine is developed to perform the conversion and flux allocation. The expression is:

[0040]

[0041] In the formula: Flus ( unsf ) represents the infiltration (or evaporation / transpiration) rate input to the MODFLOW model. Flus ( q () represents the lower boundary flux of the SWNCM-2D simulation profile. L d is the width of the SWNCM-2D simulation profile, and d is a constant value for converting the length units between models;

[0042] S13: When the simulation time changes from the first groundwater flow cumulative time step to the second groundwater flow cumulative time step, the MODFLOW model transfers the groundwater level calculated in the previous groundwater flow time step to the SWNCM-2D model as the new lower boundary condition, and recalculates and transfers the cumulative lower boundary flux within the groundwater flow time step.

[0043] S14: Repeat steps S12-S13 of the simulation process until the preset simulation time is reached.

[0044] S2. Based on the groundwater depth control test data of the lyoinfiltration meter, calibrate and verify the key parameters of the coupled model, and conduct multi-scenario simulations of different groundwater depths to determine the appropriate groundwater depth under drip irrigation conditions.

[0045] In practice, the experimental data mainly include soil moisture content, soil salinity, irrigation amount, rainfall, crop leaf area, crop height, crop yield, groundwater level, and the amount of groundwater directly pumped out or added during the maintenance of the lyostat groundwater level. The key parameters of the coupled model include soil moisture model parameters, groundwater model parameters, and crop model parameters. Soil moisture model parameters include residual moisture content, saturated moisture content, saturated hydraulic conductivity, and soil moisture characteristic curve shape parameters. Groundwater model parameters include permeability coefficient, water storage rate, and water yield in the direction of water flow. Crop model parameters include maximum crop growth temperature, minimum crop growth temperature, maximum leaf area index, and maximum heat unit value required for crop maturity.

[0046] Step S2 includes: inputting the key parameters of the coupled model as initial information into the coupled model, outputting simulated values ​​of soil moisture content, soil salinity, crop leaf area, crop plant height, crop yield, and groundwater level from the coupled model, comparing the simulated values ​​with the measured data of the experimental data for error, and adjusting the corresponding key parameters of the coupled model until the error reaches the preset range, thus completing the calibration of the key parameters; secondly, substituting the calibrated key parameters back into the coupled model, comparing the output of the coupled model with the measured data of the experimental data for error again, and if the error meets the basic standard, then the parameter verification is completed.

[0047] Step S2 also includes: setting different groundwater depth scenarios, simulating different groundwater depths using a coupled model after calibration and verification of key parameters, comparing soil salinity and crop yield results under different groundwater depth scenarios, and determining the appropriate groundwater depth as the depth corresponding to the minimum soil salinity and maximum crop yield; in particular, the appropriate groundwater depth is not constant throughout the crop's growth period, and different growth stages have different appropriate depth values.

[0048] S3. Set up scenarios with different proportions of drip-irrigated farmland and use a coupled model for simulation. Use the appropriate groundwater depth as the control standard to determine the suitable development area of ​​large-scale drip-irrigated farmland in areas with shallow groundwater.

[0049] In specific implementation, such as Figure 2 As shown, the total farmland area is A. Based on the MODFLOW model, the farmland area is divided into cells according to the simulated demand. The drip irrigation farmland area is A1, and the furrow irrigation farmland area is A2. Under different irrigation methods, the infiltration water volume per unit area from the unsaturated zone to the saturated zone is significantly different. At the same time, when the farmland area changes, the difference in infiltration water volume further increases. That is, different farmlands cause groundwater level differences, drive groundwater flow, and eventually stabilize at a certain depth.

[0050] Different scenarios with different ratios of drip-irrigated and furrow-irrigated farmland areas (the ratio of A1 to A2) are substituted into the coupled model for simulation. The coupled model outputs the simulated groundwater level values ​​corresponding to different scenarios in farmland A. The simulated groundwater level values ​​are compared with the suitable groundwater depth. The drip-irrigated farmland area in the scenario that is closest to the suitable groundwater depth is taken as the suitable development area for large-scale drip-irrigated farmland in the shallow groundwater area.

[0051] In summary, this solution systematically addresses the issues of water and salt regulation and crop response in the promotion of drip irrigation in shallow groundwater areas through multi-model coupling, multi-process simulation, and multi-scenario analysis. It provides technical support and quantitative basis for the development and field management of large-scale drip-irrigated farmland, effectively solving practical problems in the development of drip irrigation technology in shallow groundwater areas. It has strong scientific validity, practicality, and promotional value, providing important technical support and decision-making basis for the development of water-saving agriculture in similar areas.

[0052] Although specific embodiments of the invention have been described in detail with reference to the accompanying drawings, this should not be construed as limiting the scope of protection of this patent. Various modifications and variations that can be made by a person skilled in the art without inventive effort within the scope described in the claims still fall within the scope of protection of this patent.

Claims

1. A method for determining the suitable development area of large-scale drip irrigation farmland in shallow groundwater area, characterized in that, Includes the following steps: S1. Based on programming software, a coupled model was developed to simulate water and salt transport in saturated and unsaturated zones and crop growth in large-scale drip-irrigated farmland in shallow groundwater areas, using the MODFLOW model and SWNCM-2D model. Step S1 specifically includes model coupling during the preset simulation time progression, through the mutual transmission of the lower boundary flux of the SWNCM-2D model and the groundwater level simulated by the MODFLOW model. The specific process of model coupling includes: S11: When the simulation time is in the initial state, the MODFLOW model and the SWNCM-2D model read the initial information one after another, and then the initial groundwater level of the MODFLOW model is passed to the SWNCM-2D model as its lower boundary condition. S12: When the simulation time moves from the initial state to the first groundwater flow accumulation time step, the SWNCM-2D model iteratively solves the unsaturated zone soil water and salt content at a preset time step until the first groundwater flow accumulation time step is reached. Then, it outputs the accumulated lower boundary flux and passes it to the MODFLOW model, which iteratively solves the groundwater level. S13: When the simulation time changes from the first groundwater flow cumulative time step to the second groundwater flow cumulative time step, the MODFLOW model transfers the groundwater level calculated in the previous groundwater flow time step to the SWNCM-2D model as the new lower boundary condition, and recalculates and transfers the cumulative lower boundary flux within the groundwater flow time step. S14: Repeat steps S12-S13 of the simulation process until the preset simulation time is reached; S2. Based on the groundwater depth control test data of the lyoinfluence meter, calibrate and verify the key parameters of the coupled model, and conduct multi-scenario simulations of different groundwater depths to determine the appropriate groundwater depth under drip irrigation conditions. S3. Set up scenarios with different proportions of drip-irrigated farmland and use a coupled model for simulation. Use the appropriate groundwater depth as the control standard to determine the suitable development area of ​​large-scale drip-irrigated farmland in areas with shallow groundwater.

2. The method according to claim 1, wherein the method is characterized by, The SWNCM-2D model in step S1 is a coupled model of the two-dimensional soil water and salt transport mechanism model and the EPIC crop model. The two-dimensional soil water and salt transport mechanism model is solved by the finite element method. The soil moisture content and soil salt content of each finite element node in the simulation area are obtained as a function of simulation time. The water balance and node flux are used to quantify the changes in node water and salt content. At the same time, the soil water and salt data drive the EPIC crop model to simulate crop growth dynamics.

3. The method according to claim 1, wherein the method is characterized by, The MODFLOW model in step S1 is a three-dimensional groundwater transport model, which is solved using the finite difference method to obtain the groundwater level of each cell in the simulation area as the simulation time changes.

4. The method according to claim 1, wherein the method is characterized by, The MODFLOW model transfers the groundwater level to the SWNCM-2D model as a lower boundary condition, expressed as follows: where, GWL is the lower boundary condition, n is the number of cells simulated by the MODFLOW model, H i is the groundwater level corresponding to the cell; Z 1 is the bottom coordinate of the region simulated by the SWNCM-2D model.

5. The method according to claim 1, wherein the method is characterized by, The experimental data in step S2 include soil moisture content, soil salinity, irrigation amount, rainfall, crop leaf area, crop height, crop yield, groundwater level, and the amount of groundwater directly pumped out or added during the maintenance of the lysimeter groundwater level, as measured periodically during the crop growth period. 6.The method for determining suitable development area of large-scale drip irrigation farmland in groundwater shallow zone according to claim 5, characterized in that, The key parameters of the coupled model include soil moisture model parameters, groundwater model parameters, and crop model parameters. The soil moisture model parameters include residual water content, saturated water content, saturated hydraulic conductivity, and soil moisture characteristic curve shape parameters. The groundwater model parameters include permeability coefficient, water storage rate, and water yield in the direction of water flow. The crop model parameters include maximum crop growth temperature, minimum crop growth temperature, maximum leaf area index, and maximum heat unit value required for crop maturity.

7. The method according to claim 6, wherein the method is characterized by, Step S2 includes: inputting the key parameters of the coupled model as initial information into the coupled model; the coupled model outputs simulated values ​​of soil moisture content, soil salinity, crop leaf area, crop plant height, crop yield, and groundwater level; comparing the simulated values ​​with the measured data from the experimental data; and adjusting the corresponding key parameters of the coupled model until the error reaches the preset range, thus completing the calibration of the key parameters; resimulating using the calibrated key parameters; checking the error between the simulated values ​​and the experimental data; and verifying the key parameters when the error meets the requirements. 8.The method of claim 7, wherein the method further comprises: determining the suitable development area of the large-scale drip irrigation farmland in the shallow groundwater area based on the obtained suitable development area of the large-scale drip irrigation farmland in the shallow groundwater area. Step S2 also includes: setting different groundwater burial depth scenarios, simulating different groundwater burial depths through a coupled model after calibration and verification of key parameters, comparing the soil salinity and crop yield results under different groundwater burial depth scenarios, and taking the burial depth corresponding to the minimum soil salinity and maximum crop yield as the appropriate groundwater burial depth. 9.The method of claim 1, wherein the method further comprises: determining the suitable development area of the large-scale drip irrigation farmland in the shallow groundwater area based on the obtained suitable development area of the large-scale drip irrigation farmland in the shallow groundwater area. Step S3 specifically includes: setting different scenarios of drip-irrigated farmland and furrow-irrigated farmland area ratios, substituting them into the coupling model for simulation, obtaining the corresponding groundwater level simulation values, comparing the groundwater level simulation values ​​with the suitable groundwater depth, and taking the drip-irrigated farmland area in the scenario that is closest to the suitable groundwater depth as the suitable development area for large-scale drip-irrigated farmland in the shallow groundwater area.

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